Turntables

This page is still under development, and is added to along the way, now got as far as the subchassis, speed controls and motors, much more still to come

This is so much fun, how does a turntable really work?

As long as it turns at the right speed they all sound the same, right?

Dead Wrong!

Imagine going down an Olympic bobsleigh run. That's a stylus tip getting thrown around as it goes down a track

That's a stylus being driven by the groove, and it's the wrong way round from the bobsleigh, with the stylus the track is driving you!

The forces on a stylus are several tonnes per square inch and every time you are thrown from side to side you make a noise, a scream that turns into music

To extract every last movement which turns into music the stylus has to move while the cartridge body stays still. It is the relative movement that generates the signal.

The smallest movements we are measuring here are thousandths of an inch, so mechanical integrity of the cartridge, arm, tonearm, and the entire turntable are vitally important.

From a cartridge which isnt bolted in correctly, a tonearm that flexes, a main turntable bearing that has too much play, or too much noise, all these factors will lose vital information

So you can see that the mechanical integrity is vitally important, but so is keeping the mass not too much. When you make a turntable plinth or platter of very heavy materials you don't stop them vibrating, all you do is make them vibrate at a lower frequency, a frequency that may be more damaging to the overall sound.

I have also seen manufacturers making very heavy platters with useless main bearings resulting in fast wear and extra noise and vibration being introduced into the system. They very quickly sound rubbish, but I wont slander them here by naming names. When you look at and compare turntables you can very quickly see which are designed by competent engineers and which are sprinkled with fairy dust and crackpot theories dressed up as facts.

One of my favourite madnesses is turntables with 2 motors. This makes no sense at all!

Twice the noise and vibration into the system and no benefit at all. How do these things ever get into production?

Why would a hifi retailer ever stock or recommend them? Must be an idiot.

There are some simple engineering principles that show manufacturers are sensible

Low noise motors and care taken to reduce this as much as possible.

Correctly balanced platters

Rigid tonearms

Mechanically sturdy cartridges

When you look at this from an engineering point of view two manufacturers stand out.

Linn and Rega

That's not to say there aren't other good engineers about, John Michell is a good engineer, although often his designs need to conform to other pressures to use glass and gold

There are many manufacturers of expensive turntables who make a reasonable sound but often it is no better than reasonable

Compare many expensive turntables to a simple well-engineered Rega Planar 3, and very often the simple well engineered Rega sounds much better.

The engineering of the Planar uses a heavy glass platter which can be seen to be balanced as long as it has no air bubbles.

The famous one piece Rega tonearm is very rigid and uses finely matched bearings.

These follow on from the original Planar3, the plinth is now lighter but stiffer, the added bracing that you can see runs top and bottom from arm to bearing and makes this even stronger .

The motor is also upgraded and now has less vibration to be fed into the turntable system.

At just £ 550 there is nothing comes close to the performance. For £625 you can have the Planar3 with a factory fitted Elys cartridge worth £ 119

So how do you improve on this?

Rega have another 3 levels with separate power supplies to reduce motor noise and vibration, better arm bearings, better cartridges, and even more improvements with solutions from £ 1198 to £ 3698

For a step further let's see what Linn do.

In order to reduce vibrations, both airborne and mechanical, Linn have looked at every area in extreme detail.

The turntable mechanism is suspended on a subchassis hanging on three springs. These are balanced at set-up depending on the choice of arm and cartridge.

There are three levels of subchassis, so a standard LP12 can be upgraded even further

The standard subchassis can have a choice of armboards to match virtually any tonearm.

The higher levels, Kore at £ 800 and Keel at £ 2550 are an integrated subchassis and armboard.

In the case of the Keel this is machined in one piece from aluminium

An upgraded version is current in new Lp12s. The Kore pictured below is an upgrade from this and can be fitted to any LP12 with audible improvements in clarity

The Keel is the ultimate subchassis. Machined from a single aluminium billet it offers the ultimate in stiffness without resonance

This subchassis is integral to the whole performance, but just one part.

The original Linn motor, still used in most versions, is a low noise ac motor with speed taken from the frequency fed to it. Early Linns were therefore dependent on the mains frequency for the speed with a simple board.

The Valhalla kit from 1982 changed all that. Still using the ac motor the Valhalla made it's own 50Hz supply from a crystal oscillator and also reduced the voltage to the motor for less vibration. No-one had done this before and it shocked the turntable world into a reaction. Before long everyone else saw the benefits and added power supplies.

The Valhalla spawned the Lingo in 1990, a separate box power supply with better stability and another clever trick. Starting a motor means generating enough torque to get the heavy platter up to speed, yet once at speed much less is needed. The Lingo gives out a higher voltage on start up and then drops dramatically once at the correct speed reducing the noise and vibration generated by the motor dramatically. Less noise and vibration lowers the noise floor and allows the retrieval of more information from the record grooves

The Lingo went through improvements over the years, and is still available today as Lingo 3, but in 2009 a major improvement arrived.

The trusty 24 pole synchronous motor was bettered by completely new thinking, the Radikal

This new DC motor features a sophisticated control system to reduce noise and vibration to new low levels.

Below is the radikal motor, bottom is the trusty original motor that for over 30 years through many versions was the best around

The result is a much more dynamic sound resolving tiny details, the only downside? £ 2800